Abstract 11492: Hyperglicemic ’Memory’ Affects Commitment of CD34+ Cord Blood-Derived Stem Cells Into Functional Endothelial Progenitor Cells (EPCs)
Background: A decrease in circulating endothelial progenitor cells (EPCs) number and function is observed in subjects with type-1/-2 diabetes mellitus (DM). DM-related complications persist in subjects with long-term glycemic control, a phenomenon called hyperglycemic ‘memory’. In the present work we assessed whether exposure to pathologic glucose levels is sufficient to reduce the commitment of multipotent CD34+ cells from the human cord blood into functional EPCs, and this defect is maintained even after relief from hyperglycemic conditions.
Methods and Results: CD34+ cells were purified from cord blood of normal donors and expanded in a SCF (100ng/ml), Flt3L (100ng/ml), IL3/6 (20ng/ml) cytokine-supplemented serum-free culture up to 30 days in hyperglycemia (50 mM glucose, HG) or normoglycemia (25 mM glucose, NG) conditions. While cells grew with similar kinetics during the initial 10 days, the expansion of HG vs. NG cells was reduced at 20 and 30 days [fold expansion, NG vs. HG: 11.4±1.3 vs. 7.6±0.44, 20 days; 14.9±0.9 vs. 5.8±0.5, 30 days; n=6; P<0.01; 2-ways ANOVA]. The ability of CD34+ cells to form colony forming units-endothelial cell (CFU-EC) clusters was then assessed by colony assays. These tests showed that HG-CD34+ cells had a lower ability to form CFU-ECs compared with NG-CD34+ cells. Interestingly, cells that were pre-expanded in HG maintained the inability to form CFU-ECs even when the colony assays were performed in normal glucose (ex-HG condition) [number of CFU-EC clusters/3.5x105 input cells: 1.0±0.7 vs. 1.9±0.6 vs 5.4±0.6; n=4; P<0.01; HG and ex-HG vs. NG; 1-way ANOVA]. HG-CD34+ cells showed a reduced migration in response to chemokine SDF-1 even after release from HG [migration index: 2.4±0.3 vs. 2.3±0.52 vs. 5.4±0.91; n=4; P<0.01; HG and ex-HG vs. NG; 1-way ANOVA]. The inability to migrate against SDF-1 gradient was also observed in EPCs derived from HG CD34+ cells in the absence of glucose.
Conclusions: These data show that HG induces a failure of unspoiled human CD34+ cells to be committed into functional EPCs, which persists even after return to normal glycaemia. These data are consistent with the establishment of a hyperglycemia memory in multipotent CD34+ cells jeopardizing their pro-angiogenic phenotype.
- © 2013 by American Heart Association, Inc.